PURPOSE: To enable the development of the self-stress of a refractory element at a temp. of the extent for attaining the m.p. of steel by compounding cores composed of a specific second refractory material with a first refractory material constituting this refractory element.

CONSTITUTION: The cores which have the coefft. of thermal expansion smaller than the coefft. of thermal expansion of the first refractory material and are composed of the second refractory material which is enhanced in the tensile strength at a service temp. are inserted into the first refractory material constituting the refractory element. The tensile strength of the cores are preferably 60 to 3000 N/mm2. The cores can be bar-shaped objects and can, in some, cases, be materials subjected to relief on the surfaces. These cores are preferably disposed within the area of the refractory element to be subjected to a tensile stress or shearing stress. The cores are dispersed as fibers into the first refractory material. The fibers preferably have a length of 0.5 to 15 mm and a diameter of 5 to 100 μm. The examples of the raw materials for production of the cores include sintered alumina, silicon carbide, silicon nitride, cermet, carbon fibers, carbon fiber-contg. composite materials, etc.